This invention relates generally to washing machines, and more particularly, to methods and apparatus for reducing water usage and energy consumption in a washing machine.
Washing machines typically include a cabinet that houses an outer tub for containing wash and rinse water, a perforated clothes basket within the tub, and an agitator within the basket. A drive and motor assembly is mounted underneath the stationary outer tub to rotate the basket and the agitator relative to one another, and a pump assembly pumps water from the tub to a drain to execute a wash cycle. See, for example, U.S. Pat. No. 6,029,298.
Known washing machines fill large loads with almost 22 gallons of water to ensure laundry is safely wetted with detergent solution during wash cycle or rinse water during rinse cycle. Recent proposals by the Department of Energy and certain state regulatory bodies could impose standards that will require reduction in water use and overall energy use. The desired levels would not permit large loads to be properly wetted nor properly agitated during the wash cycle. Both washability and Danish wear scores have large variations across the loads under these conditions. Wash performance must be balanced against time constraints, hot water use, electrical energy use, and laundry wear.